Diffusion apparatus



F119@ June 27, 1955 K. HEINRICH DIFFUSION APPARATUS A: Bl

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Dec. 10, 1957 Filed June' 27, 1955 United States Patent Eea DIFFUSION APPARATUS Kurt Heinrich, Grevenbroich, Germany Application June 27, 1955, Serial N o. 513,228

Claims priority, applicationGermany .lune 29, 1954 9 Claims. (Cl. 127-7) The present invention relates to a diffusion apparatus, and particularly to a diffusion apparatus for extracting juices from pulp mash in countercurrent with an extracting liquid. More particularly, the invention relates to the extraction of juices from beet chipping, shreds or slices in sugar manufacture.

A diffusion apparatus is known in which pulp mash isstirred and raised by rotary arms. The apparatus according to the known art, when applied to pulp mash containing less than 60% of vegetable chippings or slices, has the disadvantage that parts of the pulp mash arek not conveyed together with the main portion of the pulp mash, but move slower or faster so that they are exposed a. longer or shorter time to the: extraction process. This results in an uneven extraction of the pulp mash which is highly undesirable.

It is one object of the present invention to overcome the disadvantages of the knowndiffusion apparatus, and to; provide a diffusion apparatus in which the entire mass of pulp mash is subjected toy a uniform extraction treatment.

It isv another object of the present invention to provide a; diffusion apparatus in. which the extractionliquid and the pulplmash move in countercurrent, at a constant relative speed.

In the event that such compression of the pulp mash can be obtained by rotating arms that the chippings constitute over 60% ofthe compressed pulp mash, the chippingsmat and form layers which are not easily displaced in, axial direction; of` the diffusion chamber.

It is consequently a further object of the present invention to provide in a diffusion apparatus rotary agitating arms, which create suctionand pressure` zones in the pulp mash that the extracting liquid may move:in axial direction through` suction Zones in which the pulp mash is more permeable.

Another objectV of` ther present invention is the provision of rotary agitating arms hav-ing streamlined crosssection and. downwardly inclined leadingA top faces for creating pressure and suctionzones in. thepulp mash.

With theseobjects in view theA present invention` mainly consists in a` countercurrent diffusion apparatus, for extracting juices from pulp mashv containing vegetabley chippings, and comprises, in combination, tank means including cylindrical wall means having a vertical axis and defining an annular diffusion chamber; a plurality of axially spaced sets. of angularly spaced stationary first arms secured to the wall means, each first arm, having an, upwardly inclined guide face; drivev means rotatable in one direction about the vertical axis; a plurality of axially spacedangularly staggered second arm means located in the annular diffusion chamber and being connected to the drive means for. movement about the axis in horizontal planes respectively located between two setsV of first arms, the second arm means includingV at least` one second arm having a streamlined cross-section, each secondi arm being elongatedE in radialy direction and narrow in transverse direction and having aA leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined trailing face for creating a suction zone i'n the pulp mash, the suction and pressure zones of secondarms following eac'n other in the direction of rotation being adapted to overlap so that an extraction liquid may passv downwardly through said suction zones in the pulp mash.

Preferably, the first arms are inclined at an angle of substantially 45 with respect to the axis of the tank. Thereby, a damming up of the pulp mash in the region of the tank walls is prevented.

In the arrangement according to the present invention a nozzle-like passage is formed between consecutive rotary agitating second arms in which due to the suction created by the leading arm the pulp mash is loosened so that the denser compressed pulp mash located forwardly of the next following arm is sucked into the suction zone of the preceding leading arm. Rearwardly of each rotary agitating second arm, the pulp mash is loosened to a considerable extent so that the extraction liquid can pass substantially in axial direction through the tank.

Thisfaction-of the rotary agitating second arms is particularly effective if these arms have a fiat or slightly convex leading top face, and a convex trailing face.

The. projection of the leading top faces of the second arms on a horizontal plane covers an area substantialiy between one-third and one-fourth of the cross-sectional area of the diffusion chamber.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a plan view of a diffusion apparatus according to the present invention;

Fig. 2 is a cross-sectional View of a rotary agitating arm taken on line II-II in Fig. l;

Figs. 3a and 3b illustrate a beet chipping in straight and bent conditions;

Fig. 4 is a schematic developed View of a diffusion apparatus according to the present invention; and

Fig. 5 is a fragmentary axial sectional view of the apparatus.

Referring now to the drawing, and more particularly to Figs. l and 2, a hollow cylindrical rotary core 2 is arranged coaxial with the outer cylindrical wall i of a diffusion tank. The core 2 is enveloped by a set of axially spaced annular wall members 4 which are connected by stationary arms 6 to the outer cylindrical wall 1 of the tank. An annular diffusion chamber is formed between the walls 2, 4 and the wall l. Two agitating arms 3, secured to the rotary core 2, project into the diffusion chamber between each two adjacent annular wall members 4. Only one agitating arm means including two agitating arms 3 is shown in Fig. l, but it will be understood that a plurality of axially spaced arm means 31 to 35, see Fig. 4, is provided in the tank, the arms 3 of axiallijI adjacent agitating arm means being angularly staggered as shown in Fig. 4. When the core member 2, which constitutes a drive means for the agitating arm means 3, rotates the agitating arms 3 in the direction of the arrow D, the leading top face 3b, best seen in Fig. 2, creates a pressure Zone in the pulp mash, while the traiiing bottom face 3c creates a suction zone in the pulp mash behind the moving agitating arm 3. The leading edge of each agitating arm 3 is inclined at an angle with respect to a radialplane, so that the outer ends of the leading edges of the agitatingv arms 3 are located for- 3 j wardly in the direction of rotation as compared with the inner ends of the same.

Stationary arms 6 connect the outer cylindrical wall 1 with the annular wall members 4 and are preferably connected by intermediate annular members S. The arms 6 have inner ends arranged forwardly in the direction of rotation with respect to the outer ends thereof. Arms 6 are inclined at an angle of substantially 45 with respect to planes passing through the vertical axis of the tank and to horizontal planes as shown in Fig. 4.

As shown in Fig. 2, the agitating arms 3 have a streamlined cross-section similar to the cross-section of an airplane wing. The leading edge has preferably a radius of curvature of substantially mm., while the trailing edge is formed with a series of recesses 3a spaced along the trailing edge of the agitating arm. The leading top face 3b is flat or slightly convex, while the trailing bottom face 3c is convex adjacent the leading edge, and slightly concave adjacent the trailing edge.

The operation of the apparatus according to the present invention will be best understood with reference to Fig. 4. While actually the agitating arms 3 move in the direction of the arrow 9 in the lower portion of Fig. 4, it will be assumed for explanatory purposes that the agitating arms 31 to 35 are at a standstill, and that the pulp mash and the stationary arms 6 move around the vertical axis of the tank as indicated by the arrows 8 in the upper portion of Fig. 4. The tank is assumed to be filled with pulp mash containing at least 60% vegetable or beet chippings.

Assuming these conditions, a pressure zone or wave is created above the leading top face 3b of the agitating arms 31 to 35. The pressure zone in the pulp mash is indicated by signs in Fig. 4. Underneath the agitating arms 31 to 35, a suction zone or wave is created which is indicated by signs. The agitating arms 31 to 35 are angularly staggered and move in horizontal planes about the vertical axis of the tank. Each agitating arm means 3 moves between axially spaced sets of stationary angularly spaced arms 6.

Rearwardly of the agitating arms 3 with respect to the direction of rotation, the pulp mash is loosened as indicated by signs. The extracting liquid, which moves in the direction of the arrows 7 along the paths of least resistance, passes the trailing edges of the agitating arms and moves toward the outlet of the diffusion tank. The chippings slide through the nozzle-like passages between consecutive agitating arms, for instance, between arms 31 and 32 in the direction of the arrows S. Rearwardly of this area with respect to the direction of movement of the agitating arms, the pulp mash has average density. This density may reach according to extensive tests such value that the volume of the solid chippings before being placed in the diffusion tank is 120% of the volume of the diffusion chamber while nevertheless the pulp mass is permeable for the extracting liquid. This effect can be explained by the shrinking of the chippings during the diffusion process. In this manner, the output of the diffusion apparatus according to the present invention is substantially higher than the output of the known diffusion apparatus.

As described above, the leading edge of the agitating arms has a radius of curvature of substantially 20 mm. whereby the efficiency of the arrangement is further mproved. Fig. 3a shows a beet chipping in straight condition. In the event that such beet chipping is bent about a radius of curvature of 20 mm. by the leading edge of an arm 3, the concave side of the chipping is compressed to such extent that the juice is pressed out of the cells and onto the surface of the chipping, whereas on the convex expanded side located on the other side of the neutral line fx1-B1 a suction effect takes place in the cells of the chipping, whereby juices are sucked from the surroundings of the chippings into the chipping cells. The

optimal effect is obtained when the radius of curvature is- 20 mm., as has been proven by tests. In the event that the radius of curvature is smaller, the chippings break, particularly when frozen, which would cause an increased pulp formation in the diffusion apparatus.

As previously explained, the actual movement of the pulp and of the chippings is indicated by arrows in the lower portion of Fig. 4. The arrow 9 indicates the direction of rotation of the agitating arms 3, the arrows 10 indicate the passage of the chippings through the diffusion chamber, and the arrows 11 indicate the path of the cxtraction liquid. It will be understood that the movement of the chippings as well as of the extracting liquid takes place in steps during each passage of an agitating arm 3.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of diffusion apparatus differing from the types described above.

While the invention has been illustrated and described as embodied in a diffusion apparatus including agitating arms creating overlapping pressure and suction zones ini a pulp mass, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tankrmeans including cylindrical wall means having a vertical axis and defining an annular diffusion chamber; a plurality of axially spaced sets of angularly spaced stationary first arms secured to said wall means and having upwardly inclined guide faces; drive means coaxial with and rotatable in one direction about said vertical axis; a plurality of axially v spaced angularly staggered second arm means located in said annular diffusion chamber and being connected to said drive means for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including at least one second arm, each second arm being elongated in radial direction and narrow in transverse direction and having a leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined trailing face for creating a suction zone in the pulp mash, the suction and pressure zones of second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mash.

2. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tank means including cylindrical Wall means having a vertical axis and de ning an annular diffusion chamber; a plurality of axiallyl means coaxial with and rotatable in one direction about: said vertical axis; a plurality of axially spaced angularlyv staggered second arm means located in said annular diffusion chamber and being connected to said drive meansv for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including at least one second arm having astreamlined cross-section, each second arm being elon-j gated in radial direction and narrow in transverse direction and having a leading top face forwardlyand downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined trailing face for creating a suction zone in the pulp mash, the suction and pressure zones of second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mass.

3. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tank means including cylindrical wall means having a vertical axis and defining an annular diffusion chamber; a plurality of axially spaced sets of angularly spaced stationary first arms secured to said wall means and located in horizontal planes each first arm having an upwardly inclined guide face; drive means coaxial with and rotatable in one direction about said vertical axis; a plurality of axially spaced angularly staggered second arm means located in said annular diffusion chamber and being connected to said drive means for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including atleast one second arm having a streamlined cross-section, each-second arm-being elongated in radial direction and narrow in transverse direction and having a rounded leading edge and a slightly convex leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined partly convex trailing face for creating a suction zone in the pulp mash and a thin trailing edge, the suction and pressure zones of the second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mash.

4. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tank means including cylindrical wall means having a vertical axis and defining an annular diffusion chamber; a plurality of axially spaced sets of angularly spaced stationary first arms secured to said wall means, each first arm having an upwardly inclined guide face; drive means coaxial with and rotatable in one direction about said vertical axis; a plurality of axially spa-ced angularly staggered second arm means located in said annular diffusion chamber and being connected to said drive means for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including at least one second arm having a streamlined cross-section, each second arm being elongated in radial direction and narrow in transverse direction and having a leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined trailing face for creating a suction zone in the pulp mash, each second arm having a leading edge and a trailing edge bounding said leading and trailing faces, said leading edge having a radius of curvature of substantially 20 mm., the suction and pressure zones of second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mash.

5. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tank means including cylindrical wall means having a vertical axis and defining an annular diffusion chamber; a plurality of axially spaced sets of angularly spaced stationary first -arms secured to said wall means, each first arm having an upwardly inclined guide face; drive means coaxial with and rotatable in one direction about said vertical axis; a plurality of axially spaced angularly staggered second arm means located in said annular diffusion chamber and being connected to said drive means for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including at least one second arm, each second arm beingelongated 1n radial direction and narrow in transverse `direction andV havinga leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having anV inclined trailing face for creating a suction zone in the pulp mash, each second arm having a leading edge and a trailing edge bounding said leading and trailing faces, saidleading edge having a radius of curvature of substantially 20 mm., said trailing edge of each second arm being formed with a series of recesses spaced along said trailing edge,r the suction and pressure zones of second arms following. each other in the direction of rotation being adaptedvrgtor; overlap so that an extraction liquid may pass ,downwardlyl through said suction zones in the pulp mash. 3 t

6. A diffusion apparatus as set forth y.inclaim .lwherein said annular diffusion chamber has a -predeterminedcross-` sectional area in a` horizontal plane, and wherein the, projection of said leadingtop faces of said second arms onJ a horizontal plane covers an area substantially between one-third and one-fourth of said predetermined cross-` sectional area of said annular diffusion chamber. 2

7. In a countercurrent diffusion apparatusfor extracting juices from pulp mash, in combination, tank means `in: cluding cylindrical wall means having a vertical axiszand; defining an annular diffusion chamber; a plurality of axially spaced angularly staggered sets of angularly spaced stationary first arms secured to said wall means and located in horizontal planes, each first arm having an upwardly inclined guide face; drive means coaxial with and rotatable in one direction about said vertical axis; a plurality of axially spaced angularly staggered second arm means located in said annular diffusion chamber and being connected to said drive means for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including a plurality of second arms, each second arm being elongated in radial direction and narrow in transverse direction and having a leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined trailing face for creating a suction zone in the pulp mash, each second arm having a rounded leading edge and a thin trailing edge bounding said leading and trailing faces, said first arms having outer ends located rearwardly in direction of rotation With respect to the inner ends thereof, and said second arms having inner ends located rearwardly in direction of rotation with respect to the outer ends thereof, the suction and pressure zones of second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mash.

8. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tank means including cylindrical wall means having a vertical axis and defining an annular diffusion chamber; a plurality of axially spaced angularly staggered sets of angularly spaced stationary first arms secured to said wall means and located in horizontal planes, each first arm having an upwardly inclined guide face; drive means coaxial with and rotatable in one direction about said vertical axis; a plurality of axially spaced angularly staggered second arm means located in said annular diffusion chamber and being connected to said drive means for movement about said axis in horizontal planes respectively located between two sets of first arms, each second arm means including a plurality of second arms, each second arm being elongated in radial direction and of uniform transverse width, each second arm having a slightly convex leading top face forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined partly convex trailing face for creating a suction zone in the pulp mash, the

7 suction and pressure Zones of second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mash.

9. In a countercurrent diffusion apparatus for extracting juices from pulp mash, in combination, tank means including inner and outer cylindrical wall means having a vertical axis and defining an annular diffusion chamber, said inner wall means including axially spaced annular members located in horizontal planes; a plurality of axially spaced sets of angularly spaced stationary tirst arms secured to said outer wall means and to said annular members, each first arm having an upwardly inclined guide face extending at an angle of substantially 45 with respect to said vertical axis; drive means coaxial with and located within said inner cylindrical wall means and ineluding a rotary core member rotatable in one direction about said vertical axis; a plurality of axially spaced angularly staggered second arm means located in said annular diffusion chamber and being connected to said rotary core member of said drive means for movement about said axis in horizontal planes respectively located between two sets of tirst arms, each second arm means including two diammetrically arranged second arms located in the same horizontal plane and having a streamlined cross-section, each second arm being elongated in radial direction and narrow in transverse direction and having a leading top face extending transverse to said guiding faces of said first arms and being forwardly and downwardly inclined in the direction of rotation for compressing pulp mash in a pressure zone, each second arm having an inclined trailing face for creating a suction zone in the pulp mash, each second arm having a rounded leading edge and a recessed thin trailing edge bounding said leading and trailing faces, said rst arms having outer ends located rearwardly in direction of rotation with respect to the inner ends thereof, and said second arms having inner ends located rearwardly in direction of rotation with respect to the outer ends thereof, the suction and pressure Zones of second arms following each other in the direction of rotation being adapted to overlap so that an extraction liquid may pass downwardly through said suction zones in the pulp mash.

References Cited in the tile of this patent UNITED STATES PATENTS 2,550,947 Straight May 1, 1951 2,637,666 Langen May 5, 1953 2,663,623 Anderson Dec. 22, 1953 

1. IN A COUNTERCURRENT DIFFUSION APARATUS FOR EXTRACTING JUICES FROM PULP MASH, IN COMBINATION, TANK MEANS INCLUDING CYLINDRICAL WALL MEANS HAVING A VERTICAL AXIS AND DEFINING AN ANNULAR DIFFUSION CHAMBER; PLURALITY OF AXIALLY SPACED SETS OF ANGULARLY SPACED STATIONARY FIRST ARMS SECURED TO SAID WALL MEANS AND HAVING UPWARDLY INCLINED GUIDE FACES; DRIVE MEANS COAXIAL WITH AND ROTATABLE IN ONE DIRECTION ABOUT SAID VERTICAL AXIS; A PLURALITY OF AXIALLY SPACED ANGULARLY STAGGERED SECOND ARM MEANS LOCATED IN SAID ANNULAR DIFFUSION CHAMBER AND BEING CONNECTED TO SAID DRIVE MEANS FOR MOVEMENT ABOUT SAID AXIS IN HORIZONTAL PLANES RESPECTIVELY LOCATED BETWEEN TWO SETS OF FIRST ARMS EACH SECOND ARM MEANS INCLUDING AT LEAST ONE SECOND ARM, EACH SECOND ARM BEING ELONGATED IN RADIAL DIRECTION AND NARROW IN TRANSVERSE DIRECTION AND HAVING A LEADING TOP FACE FORWARDLY AND DOWNWARDLY INCLINED IN THE DIRECTION OF ROTATION FOR COMPRESSING PULP MASH IN A PRESSURE ZONE OF SECOND ARMS HAVING AN INCLINED TRAILING FACE FOR CREATING A SUCTION ZONE IN THE PULP MASH, THE SUCTION AND PRESSURE ZONES OF SECOND ARMS FOLLOWING EACH OTHER IN THE DIRECTION OF ROTATION BEING ADAPTED TO OVERLAP SO THAT AN EXTRATION LIQUID MAY PASS DOWNWARDLY THROUGH SAID SUCTION ZONES IN THE PULP MASH. 